1. Field of the Exemplary Embodiments
Apparatuses and methods consistent with exemplary embodiments relate to a backlight unit and a display apparatus having the same, and more particularly, to a backlight unit using electron emission elements and a display apparatus having the same.
2. Description of the Related Art
A liquid crystal display (LCD) apparatus, which is a representative display apparatus, comprises a liquid crystal panel which displays images and a back light unit (BLU) which is disposed on a rear surface of the liquid crystal panel and radiates light towards the liquid crystal panel.
A back light unit (BLU) has a light source for generating light. Cold cathode fluorescent lamps (CCFL) and light emitting diodes (LED) have mainly been used as light sources. Recently, new types of back light units which use electron emission elements are being developed.
A back light unit (BLU) using electron emission elements comprises a pair of substrates, that is, a first substrate (upper substrate) and a second substrate (lower substrate). On the lower substrate, a plurality of electron emission elements and cathode electrodes are disposed, whereas on the upper substrate, a fluorescent substance layer and an anode electrode are disposed. When an electric field is formed between the cathode electrodes and the anode electrode, electrons are emitted from the electron emission elements, and as the emitted electrons collide with the fluorescent substance layer, light is generated.
A type of cathode electrode may comprise a terminal portion (dummy) where voltage is applied and a plurality of thin electrode strips which are extended from the terminal portion. During the process of manufacturing a back light unit (BLU) which uses electron emission elements, excitations or cracks may often occur in the area near the electrode strips adjacent to the terminal portion due to a difference between the thermal expansion coefficient of the material of the electrode strips relative to those of other materials. And if such cracks get worse, the electrode strips may break.
A break of the cathode electrodes may act as a fatal defect in the back light unit (BLU), and thus there is a need to resolve this problem.